This invention relates to roofing material, and in particular to roofing shingles, having a novel backing which imparts improved characteristics such as resistance to damage from hail.
Roofing material has a front upper surface, at least a portion of which is intended to be exposed to weather, and a back lower surface facing in the direction opposite to the upper surface. Traditionally, the back, non-weather-exposed surface of roofing material such as shingles has been covered with finely ground mineral material (“fines”) so that the asphalt backing does not adhere to contiguous roofing material when packaged for transport and storage. Such finely divided materials include mica flakes, copper slag, coal slag, sand, talc and silica dust.
In many regions the roofing materials on buildings, particularly the shingles on residential dwellings, are damaged by hail. The damage is caused by the impact of the hail stones on shingles resulting in visible cracking, tearing, snapping or imperceptible damage to the shingles' structure which can render the shingles less resistant to the elements of wind, rain, snow and ice. Frequently, such damage requires the costly replacement of roofing materials to prevent the elements from entering into the building.
U.S. Pat. No. 6,341,462 B2, to Kiik et al., discloses a roofing material with improved resistance to damage by hail having an energy-absorbing backing layer adhered to its lower surface. The backing layer of U.S. Pat. No. 6,341,462 comprises fiber and binding components with a combined weight ranging between 0.5 and 5 lbs. per square (100 square feet) of shingle material such that the exposed portion of a shingle made according to U.S. Pat. No. 6,341,462 appears more substantial and is, indeed, visibly thicker prior to application than products made without the backing layer.
It is an object of the present invention to provide roofing materials, particularly shingles, which have a reduced susceptibility to damage during hail storms, and are nevertheless lightweight and simple to manufacture and package using conventional equipment.